Electrical devices connected together through a network can communicate with one other, even if some of the devices are not in close proximity to the other devices. Some networks connect electrical devices in a small area, such as a single room or building, while other networks connect electrical devices in a much larger area, such as different parts of a country or the world. Examples of networked electrical devices include routers, bridges, gateways, servers, and individual computer workstations.
In order to keep a network functioning properly and to deal efficiently with network problems, a network manager periodically gathers information about all of the devices connected to the network, and maintains that information, in, e.g., a database. As used herein, the term “discovery” refers to the process of gathering such network information, and “discovery system” refers to the collection of hardware components and associated software used in the discovery process. For each network discovery, the network manager must combine the newly gathered information with the previously known network information stored in the database. As used herein, the term “merge” refers to the process of combining new network information with the previously known network information.
Several events can change the information associated with a network (referred to herein as network or device configuration). For example, rebooting one or more of the electrical devices in the network can change the configuration of those devices. Also, changing one or more components (e.g., an interface card) of a network device, or updating the software in the network device can change the configuration of the device.
The network configuration may change to modify network connectivity, i.e., to reroute data paths to/from a network device. This case typically involves modifying the network device in some respect, without adding or removing a network device. Network configuration may also change to increase network capacity, which typically involves adding a new network device.
When combining newly gathered network information with previously known network information, it is sometimes difficult to match corresponding devices that have different configuration data. For example, replacing several interface cards in a router may result in significantly different configuration data associated with the router (e.g., different IP addresses, different unique device identification numbers, etc.). Even though the merge should indicate the router with the new interface cards is simply an updated version of the previously known router, the changes can make that determination ambiguous. In other words, it may be difficult to distinguish between a modified network device and an entirely new network device.